Update copyright headers (#2184)

* Updated source file copyright headers to remove "Copyright by the Board of Trustees
of the University of Illinois", which is kept in the top-level COPYING file.

java/src/hdf/hdf5lib/exceptions/HDF5ReferenceException.java

@@ -1,6 +1,5 @@
 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
  * Copyright by The HDF Group.                                               *
- * Copyright by the Board of Trustees of the University of Illinois.         *
  * All rights reserved.                                                      *
  *                                                                           *
  * This file is part of HDF5.  The full HDF5 copyright notice, including     *